<!DOCTYPE html>
<html>
<head>
	<meta charset="utf-8">
	<meta name="viewport" content="width=device-width, initial-scale=1">
	<title></title>
	<style type="text/css">
		*{
			margin: 0;
			padding: 0;
		}
		.ab{
			font-size: 40px;
			font-weight: bold;
			margin: 10px;
			margin-right: 0;
		}
		.bc{
			font-size: 30px;
			font-weight: bold;
			margin-bottom: 10px;
			margin-left: 10px;
		}
		.ad{
			width: 400px;
			height: 200px;
			margin: 30px;
			margin-right: 0;
			margin-bottom: 0;
			background-color: white;
		}
		.da{
			height: 300px;
			background-color: #777;
			padding: 1px; 
		}

	</style>
</head>
<body>
	<div class="da">
		<h1>dwa da daw d a </h1>
		<div class="ad">
			<p class="ab">工具</p>
			<p class="bc">计算机</p>
			<p class="bc">模型</p>
		</div>
	</div>

</body>
</html>